var bomb;
var second;

function Bomb(){
    this.start = () => {
        bomb = setTimeout(() => {
            console.log("爆炸")
        },3000);
    }
    this.clear = () => {
        clearTimeout(bomb);
    }
}

var b1 = new Bomb();
var b2 = new Bomb();

b1.start();
b2.start();
second = setTimeout(() => {
    b2.clear();
},1000);